k-omega SST SAS High Wavenumber Damping Limiter

PonchO · September 16, 2014, 09:26

Hello to everyone

,

i am trying to use the k-omega SST SAS model for my simulation.
By taking a look into the source code i recognized that the OpenFOAM-Version is very different from current versions proposed in the literature.

Besides the different formulation of the $P_{SAS}$ term in the $\omega$ -equation, the von-Karman length in newer papers is something like this:

$L_{vK}=max\left(\frac{\kappa\,S_2}{|\nabla^2\underline{u}|},HWDL\right)$

However, the OpenFOAM-2.3.x version reads

$HWDL=C_{s}\Delta$

whereas Egorov and Menter [1] propose the following:

$HWDL=C_s\,\Delta\sqrt{\frac{\kappa\zeta_2}{\frac{\beta}{C_{\mu}}-\alpha}}.$

Question 1: Did i understand it right, that OpenFOAM does not include the high wavenumber damping correctly? And what do you suggest for implementation?

The latter HWDL is based on the Smagorinsky SGS.
But taking a look into [2] the authors say, that a Smagorinsky SGS might not work well.
They propose, that it is better to construct a HWDL from a WALE SGS model.
Unfortunately, i don't have access to the reference [23] they give in [2].
Question 2: What do you think about that? Does this HWDL has that big impact on the results?

Maybe someone is familiar with the model as well as its different versions and brings a little bit light into the darkness

.

Best regards,

Christoph

[1] Egorov, Y., and F. Menter. "Development and application of SST-SAS turbulence model in the DESIDER project." Advances in Hybrid RANS-LES Modelling. Springer Berlin Heidelberg, 2008. 261-270.

[2] Menter, F. R., and Y. Egorov. "The scale-adaptive simulation method for unsteady turbulent flow predictions. Part 1: Theory and model description." Flow, Turbulence and Combustion 85.1 (2010): 113-138.

jherb · October 29, 2014, 07:15

Did you find any answers to your questions?

(Your missing reference can be found as printed book in several libraries in Germany, so you should be able to order it as "Fernleihe" from any university library: http://kvk.ubka.uni-karlsruhe.de/hyl...bit_redirect=1)

PonchO · October 29, 2014, 09:18

Hi Joachim,

i just used the plain OpenFOAM model for my first SAS simulations. The next step is to implement the standard model from CFX and Fluent into OpenFOAM, which is based on a Smagorinsky-like HWDL. I will check the deviations by simulating a wake flow behind a triangular cylinder [1].
Afterwards, i will try to couple the model with the WALE-SGS or the Vreman-SGS. If you know a good testcase for validation of flows, where the turbulent viscosity should vanish in certain regions, then feel free to reply :-).

Its just a side project. So it may take some time ;-).

Best regards.

Christoph

[1] Zhang, Xing, and Blair Perot. "Turbulent Vortex Shedding From Triangle Cylinder, Using the Turbulent Body Force Potential Model." Proceedings of ASME Fluids Engineering Division, FEDSM2000-11172, Boston, Massachusetts (2000).

PonchO · October 29, 2014, 09:20

So i don't found any answers regarding the different implementations...;-)

kingjewel1 · March 16, 2016, 06:41

Hi guys,

Any updates on this one?

zordiack · March 21, 2016, 12:01

I recently made one implementation based on the 2010 papers, you can check it out here:

http://www.cfd-online.com/Forums/ope...nce-model.html

EDIT: Just noticed you are using LES, never mind

September 16, 2014, 09:26	k-omega SST SAS High Wavenumber Damping Limiter	#1
PonchO New Member Christoph Kratzsch Join Date: Nov 2011 Location: Freiberg Posts: 28 Rep Power: 14	Hello to everyone , i am trying to use the k-omega SST SAS model for my simulation. By taking a look into the source code i recognized that the OpenFOAM-Version is very different from current versions proposed in the literature. Besides the different formulation of the $P_{SAS}$ term in the $\omega$ -equation, the von-Karman length in newer papers is something like this: $L_{vK}=max\left(\frac{\kappa\,S_2}{\|\nabla^2\underline{u}\|},HWDL\right)$ However, the OpenFOAM-2.3.x version reads $HWDL=C_{s}\Delta$ whereas Egorov and Menter [1] propose the following: $HWDL=C_s\,\Delta\sqrt{\frac{\kappa\zeta_2}{\frac{\beta}{C_{\mu}}-\alpha}}.$ Question 1: Did i understand it right, that OpenFOAM does not include the high wavenumber damping correctly? And what do you suggest for implementation? The latter HWDL is based on the Smagorinsky SGS. But taking a look into [2] the authors say, that a Smagorinsky SGS might not work well. They propose, that it is better to construct a HWDL from a WALE SGS model. Unfortunately, i don't have access to the reference [23] they give in [2]. Question 2: What do you think about that? Does this HWDL has that big impact on the results? Maybe someone is familiar with the model as well as its different versions and brings a little bit light into the darkness . Best regards, Christoph [1] Egorov, Y., and F. Menter. "Development and application of SST-SAS turbulence model in the DESIDER project." Advances in Hybrid RANS-LES Modelling. Springer Berlin Heidelberg, 2008. 261-270. [2] Menter, F. R., and Y. Egorov. "The scale-adaptive simulation method for unsteady turbulent flow predictions. Part 1: Theory and model description." Flow, Turbulence and Combustion 85.1 (2010): 113-138. jherb likes this.

October 29, 2014, 09:18		#3
PonchO New Member Christoph Kratzsch Join Date: Nov 2011 Location: Freiberg Posts: 28 Rep Power: 14	Hi Joachim, i just used the plain OpenFOAM model for my first SAS simulations. The next step is to implement the standard model from CFX and Fluent into OpenFOAM, which is based on a Smagorinsky-like HWDL. I will check the deviations by simulating a wake flow behind a triangular cylinder [1]. Afterwards, i will try to couple the model with the WALE-SGS or the Vreman-SGS. If you know a good testcase for validation of flows, where the turbulent viscosity should vanish in certain regions, then feel free to reply :-). Its just a side project. So it may take some time ;-). Best regards. Christoph [1] Zhang, Xing, and Blair Perot. "Turbulent Vortex Shedding From Triangle Cylinder, Using the Turbulent Body Force Potential Model." Proceedings of ASME Fluids Engineering Division, FEDSM2000-11172, Boston, Massachusetts (2000). mj.foamer likes this.

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October 29, 2014, 07:15		#2
jherb Senior Member Joachim Herb Join Date: Sep 2010 Posts: 650 Rep Power: 21	Did you find any answers to your questions? (Your missing reference can be found as printed book in several libraries in Germany, so you should be able to order it as "Fernleihe" from any university library: http://kvk.ubka.uni-karlsruhe.de/hyl...bit_redirect=1)

October 29, 2014, 09:20		#4
PonchO New Member Christoph Kratzsch Join Date: Nov 2011 Location: Freiberg Posts: 28 Rep Power: 14	So i don't found any answers regarding the different implementations...;-)

March 16, 2016, 06:41		#5
kingjewel1 Senior Member Join Date: Jul 2009 Posts: 260 Rep Power: 17	Hi guys, Any updates on this one?

March 21, 2016, 12:01		#6
zordiack Member Pekka Pasanen Join Date: Feb 2012 Location: Finland Posts: 87 Rep Power: 14	I recently made one implementation based on the 2010 papers, you can check it out here: http://www.cfd-online.com/Forums/ope...nce-model.html EDIT: Just noticed you are using LES, never mind